I always swap my coins (in Europe they are called "stars") for Wii-Points.
Considering that you get 250 Coins/Stars for a product (I don't really know - all I know is that you sometimes get 250 for a Wii game)

Then you have:
41 x 250 = 10250 Coins/Stars
In the WiiPoints shop you can get 100 Wii-Points for 400 Stars.
So in the best case, you could earn 10250 Stars for registering all these cards.
And then swap them for 2562 Wii-Points. And 2500 Wii-Points are worth 25 Euro (I think that are ~GBP 20,00.)

But, as I mentioned, I don't know if you really get 250 Coins for a game and if Coins/Stars values are the same in Germany and England.